In North America today pipeline construction is not keeping up with expansion of oils sands mining, SAGD projects and other heavy oil extraction techniques. Currently producers use condensate and light oils (diluent) gathered from western Alberta oil fields to dilute the heavy crude oil so that is will meet pipeline specifications and ultimately flow as freely in the pipelines as Western Canadian Select. Sources of the diluents include the Beaver Hill Lakes, Bigstone, Devon, Unicol, Gold Creek, Pass Creek, Tony Creek, Snipe Lake, Obed and plays such as the Montney plays, Duvernay plays and other fields. One clear reaction of increased heavy oil prices is that the “light” condensate oil supply is becoming gradually heavier due to the economic advantages drillers are experiencing from producing heavy oils. This western Alberta industry swing from production of 680 kg per m3 oil to heavier 800 plus kg per m3 specific gravity ultimately means less effective diluent which industry wide translates into greater dilution at a greater cost.
The diluents currently used are from routine bulk production facilities and its composition, although monitored and regulated, is not specifically designed to reduce viscosity in specific oils. Chemicals, polymers and DRAs are used in pipelines to try and get oil to flow but generally they cause fouling of upstream processes, process equipment and vessels, specifically where heat or pressure is used to refine or separate product. Many polymers and chemicals are used to clean vessels but many are water based and cause emulsion problems in pipelines and process vessels.
Heavy oil producers are currently using approximately one barrel of condensate for the transportation and upgrading of two barrels of heavy or very heavy oil. With the oil sands production projected to climb from the current 1.8 million barrels of oil in 2013 to an estimated 5.3 million barrels by 2020, this would mean an increased usage of 1.2 million barrels of condensate diluent. This predicted steep increase in demand for light oils has and will continue to make diluents a sought after commodity. Although industry groups have developed elaborate extraction processes, mechanical processes and transportation systems focused on the recycling of these diluent hydrocarbons, the oil industry as a whole has not yet escaped the high cost of recycled transportation or the inevitable high percentage losses that happen during the refining process. The amount of diluent present and the corresponding costs depress oil pricing incrementally.
Often consumers and financial marketers think of crude oil as a single element, like that of gold, or as separate brands, but in fact oil is a collection or spectrum of different molecules. Oil removed from oil sands and other bitumen operations contain several components including carbon, sulfur, oxygen, hydrogen, water, acids, bases, olefins, cycloaromatics, and salts. Carbon chains can range in length from single carbons to long chain hydrocarbons in excess of 150 carbons. Oil is a dynamic fluid which is constantly evolving in reservoir. Crude oils in separate reservoirs are as unique as fingerprints and are in unique stages of decomposition, more specifically understood as slow thermal maturation. The very elements and paramagnetic species that make up the oil also act as catalysts and radicals to decompose it into a simpler shorter chains, which creates a more volatile product. The most dense and viscous oils contain asphaltenes that form highly stable nanoparticles within oil due to the types of bonding (acid base interactions, hydrogen bonding, coordination complexes, associated molecular groups and aromatic stacking) that they undergo. These large highly stable molecules ultimately can seal up reservoir seams, impede pipes and facilities and ultimately impede flow in the large continental pipelines.
Once the nature of the specific heavy oil is understood it can be considered in mathematical context with its condensate diluents. Formulations that meet specified pipeline specifications and ultimately yield highly effective formulas or safer benzene free alternatives are most advantageous.
Diluent is added to the heavy oils to reduce viscosity but there has also been industrial usage of polymers or other elemental or surfactant based compounds to achieve viscosity benefits. Generally these compounds are known as drag reducing agents (DRA's). This general technique of adding non-like compounds, however, is best described as “chemical warfare”. These chemical cocktails can interact in pipes and processing facilities, corroding pipelines, vessels sometimes destroying compressors, fouling process towers, pumps and large scale production equipment. This warfare leads to pipeline integrity and corrosion issues which are ultimately precursors to pipeline failures and environmental damage.
Using “like” chemicals in pipelines ultimately means less chemical interactions in pipelines and less chemical precipitation in process equipment down line. These products may also be useful in the preparation of pipelines for smart pigging or for re-establishing flow in lines restricted by heavy oil. Ultimately reduced corrosion and better more effective preventative maintenance monitoring information means less down time for the pipeline, upgrading and refining systems and in turn most certainly equates to more oil shipped to be made into more final product with less environmental impact.
Currently producers in Alberta are adding between 6% and 33% diluent to their heavy production oils in order to get them to flow and meet pipeline specifications. This means that these pipelines have 6-33% less oil in them than they could otherwise. When oil isn't being shipped through the pipeline it is being hauled in trucks or shipped in overland train cars. Shipping such as this is less cost effective than pipelines and also has more environmental risk, which translates into greater risk to the public. The public is showing increased concern regarding transportation of heavy oil through populated areas and environmentally sensitive areas. Recent oil platform failures, train derailments and pipeline corrosion failures have been gaining media attention. As oil production in northern Alberta ramps up to meet continental needs, proposals to simultaneously increase the size of pipeline transportation systems have been slowed. This means that with every month there are more trains and more trucks transporting crude oil across and through our public infrastructure. The use of excessive amounts of diluent is wasteful, uneconomical, produces excess environmental footprint and ultimately wastes a non-renewable resource.
Intercontinental transport of heavy oil as undiluted bitumen is also gaining favor as it has proven to have increased cost benefits to some producers. Although this has an economic benefit in that 30% condensate diluent is not added, it does not have the volume of impact that would be intuitively believed. Tank cars are loaded with heated heavy oil and then pulled by diesel train engine to the southern or central US where they are unloaded. When they are unloaded by refineries they are drained to the extent possible. However, oil that cooled on the walls of the tank cars or was in contact with the bottom of the car becomes so viscous that it cannot be removed. Few southern refineries have heated unloading facilities to remove this viscous oil. Thus one third full tank cars are returned north to refill. This wasteful cycle is repeated until the cars are finally purged of their solidified oil. This is a very inefficient use of transportation having a high environmental toll. Using a viscosity reducer that fluidizes the oil during rail transport to refineries in the south would allow full extraction of the oil from the tank cars and thereby reduce the number of cars required, effectively reducing cost and environmental and public impact.
Developing a diluent that can be used at lower volumes and with the same flow characteristics within a pipe means one can greatly increase efficiency of existing transportation systems. This would mean more room in the pipeline, fewer trucks on public roads, less environmental impact, and fewer train cars to ship the same volume of oil. Ultimately it could cause a dynamic shift in the way oil is priced.